Although it has not been proven that ∆GLP-1 is a risk factor for T2DM, by looking at the response of GLP-1 after glucose loading, there seemed to be a tendency of decreasing response of GLP-1 among subjects with T2DM (∆ = 0.43 pg/L) compared to subjects with NGT (∆ = 0.55 pg/L) (Figure 1). This evidence concerns the gene GCG and type 2 diabetes mellitus.